Digger tooth construction



' Nov. 25, 1958 M. L lARD ETAL 2,861,362

- DIGGER TOOTH CONSTRUCTION Filed Ma :51, 1956 Maurice LIA/M49 Lionel LIA/2D BY Mm United States Patent DIGGER TOOTH CONSTRUCTION Maurice Liard and Lionel Liard, Juliette, Quebec, Canada Application May 31, 1956, Serial No. 588,494 7 Claims. C1. 37-142 The present invention relates to an improved digger tooth construction of the character in which a socketed digging point is removably mounted on the tang of a supporting body carried by the digging bucket or the like, the tooth point being releasably locked on the tang to permit detachment for resharpening or replacement thereof, by a locking means embodying a keeper held in position by a resilient element.

The main object of the present invention is the provision, in a two-part digger tooth construction of the character described, of locking means which will positively lock the tooth point on the tang under all conditions of use of the digger tooth and which is nevertheless easily rendered inoperative to unlock the tooth point from the tang.

Yet another important object of the present invention is the provision of a locking structure for a two-part digger tooth which provides a keeper mounted in the tang and engageable witha recess in the tooth point and so arranged that said keeper will always keep the tooth point in firm seating engagement with the tang despite 2,861,362 Patented Nov; 25, 1958 point has a wedge shape which provides adigging forward edge 6 which is the junction of the top and bottom 3 face the forward face 2 of the body 1 with a slight cleardeformation of the tooth point and rearward movement thereof on the tang under heavy repeated shocks.

Still another important object of the present invention is the provision of a locking structure of the character described which positively prevents relative movement between the tooth point and the tang, there being no resilient means interposed in the locking structure between said two elements.

Another important object of the present invention is the provision of a locking structure of the character described which is inexpensive to manufacture and simple to operate.

The foregoing and other important objects of the present invention will become more apparent during the following disclosure and by referring to the drawings in which:

Figure l is a perspective view of the drigger tooth in assembled position;

Figure 2 is a longitudinal section along line 22 of Figure 1;

Figure 3 is a perspective view of the keeper; and

Figure 4 is a geometric diagram of the path described by the outer edge of the keeper and of the curved locking surface of the tooth point.

Referring now more particularly to the drawings in which like reference characters indicate like elements throughout, the digger tooth, according to the present invention, comprises a supporting body 1 having means, not shown, for securing the same to the digging edge of a bucket or the like, and provided at its forward face 2 with an integral forwardly projecting tang 3 of outwardly tapered shape and having a base 4 with a cross-sectional area substantially smaller than the cross-sectional area of the front face 2 of the body 1, so as to provide a shoulder on said body to serve as an abutment surface for the rear end of the removable tooth point. The tooth ance as indicated at 12. Similarly, a small clearanceis provided, asindicated at 13, between the small front face 14 of the tang 3 and the bottom 15 of the socket 10.

When the tooth 5 is in assembled position on the tang 3, the inner faces of the top and bottom wedge surfaces 7 and 8 are in seating contact with the top and bottom wedge surfaces of the tang 3. Also the tapered side surfaces of the tang 3 are in gripping contact with the inner faces of the side walls 9 of the tooth point ,5, said inner faces being inclined with respect to the outer face of said side walls.

According to the present invention, the top portion of the tang 3 adjacent the forward face 2 of the body 1 is cut out transversely of said tang to provide a transverse recess 20 extending from one side face to the other side face of the tang 3. Said recess 20 forms a channel of rectangular cross-section and provides an upright face 21 substantially parallel with the forward face '2 of the body 1, and a bottom face 22 which is disposed at substantially right-angles to the forward face of the body 1. A shelf-like projection 23 is formed at the junction of the faces 21 and 22 and extends substantially the whole length of the recess 20.

A groove 24 of curved cross-section is made in the upright wall 21 adjacent the top of the shelf-like projection 23. Thegroove 24 serves as a seating surface for the curved pivoted edge 25 of a keeper 26.

The keeper 26 consists in a plate-like member of strong metal and extends throughout the whole length of the recess 20 and its pivoted edge 25 is in free pivotal engagement with the groove24.

The keeper 26 is provided with a square opening 27 adjacent its circular pivotal edge 25 for loosely and freelyv receiving a retainer member 28 which is secured in the bottom face 22 of the recess 20. The upper curved end 29 of the member 28 engages the opening 27 of the keeper 26 and is directed towards the upright face 21 of the recess 20 in order to prevent disengagement of the keeper from the recess 20. i

The portion of the tooth point overlying the recess 20 is provided in the top face 16 of the socket 113 with a transversely extending groove 30 which faces the recess 20 of the tang 3 and extends substantially the entire length of said recess 20. The groove 30 is constituted by a rearwardly upwardly inclined straight face 31 which adjoins with the top face 16 of the socket 10 at its front edge and which at its rear edge joins with a curved locking face 32 which constitutes the other face of the groove 30, the latter having generally the shape of an inverted V.

The locking face 32 is disposed opposite the pivotal groove24 of the keeper 26 but has its centre of curvature 34 (see Figure 4) slightly offset with respect to the pivotal axis 35 of the keeper 26. More particularly the center of curvature 34 is rearwardly and downwardly disposed with respect to the pivotal axis 35, so that the pivotal movement of the keeper will cause its outer edge 33 to describe a path, indicated at 36 in Figure 4, which crosses the curved face 32 of the groove 30 of the tooth point. Thus the keeper 26 will be kept in engagement with said locking face 32 at the junction of the two curves, shown in Figure 4, for one given position of the tooth point on the tang 3. If, under shock imparted to curved lockin'g face 32. The coil spring -37 is "upwardly,

forwardly-inclined with respect to the forward face 2 i thebody l and its upper end curls around a lug 38 made in the underface of the keeper 26, whileits flower-end portion engages an inclined'bore39 made ihthe =bottom face 22 of the recess '20.

In order to unlock the keeper 26, top wedge surface 7 of the tooth point is provided with'an inclined bore 40 which opens within the groove 30 at the inclined straight face 31 thereof. A suitable tool can 'be inserted-through bore 40 and applied against the upper face of the keeper 26 to press the latter inwardly against the action of the coil spring 37 into an inoperative unlocking position clearing the edge 41 of the tooth point. T he'e'dge 41 is at a lower level than the top face 16 of the socket a prevent the keeper from accidentally clearingsaid edge 41.

From the foregoing it will be clear thatthe keeper '26 will always maintain the tooth point in firm gripping engagement with the tang 3 despite -successive"'s'hocks imparted to the tooth duringdigging. Successive shocks will only cause further engagement of the tooth-point on the tang and said tooth pointwill be kept-iii 'the la'stposition by the keeper'which will move gradually upwardly under the action'of the spring 37.

It will be noted that the main stresses exerted on the tooth during work will not be transmitted as compression forces on the keeper because the latter is rearwardly,

upwardly directed with respect to'the tooth points While a preferred embodiment according tosthelp'resent invention has been illustrated and described it is understood that various modifications may be resorted to without departing from the spirit and scope of the appendedclaims.

We claim:

1. A digger tooth construction including a'body having a tang, a tooth point removably mounted on saidtang, a cut out portion in said tang adjacent said body, a keeper pivotally mounted in said cut outportion of said itang about a transverse axis with respect to said tang,.said point having a groove which, when said point 'is .in assembled position on said tang, faces said keeper, said groove having a curved face engageable by the outenend of said keeper, said curved face having its axis of curvature oifset with respect to the pivot axis of said keeper,'

said axis of curvature being disposedrearwardlyfrom said pivotal axis, and resilient means disposed between said keeper and the bottom of said cut out portion of said tang and urging said keeper into groove engaging position.

2. A digger tooth construction as claimed in claim 1, further including a bore made in said tooth point and providing access to said keeper for moving the same out of groove engaging position.

3. A digger tooth as claimed in claim 1, wherein said resilient means consists of a coil spring having one end contacting the underface of said keeper and the other end engaging a bore made in the bottom face of the cut out portion of said tang.

4. A digger'tooth construction as claimed in claim '2, further including means to attach saidkeeper'to said tang 4 while allowing for free pivotal movement of said keeper.

5. A digger tooth construction "as claimed in claim 2, wherein said keeper is directed toward the body to lock said point against movement'away from said body.

6. A digger tooth construction comprising a body adapted to be attached to the digging edge of a bucket or the like, and having a forward face, a tang projecting forwardly, outwardly fro'mthe forward face of said body and having a tapered shape, the base of said tang being smaller in *cross 's'ection than said forward face of said body to provide ashioulder surrounding said tang, said tang having an upper face provided with a transverse'cut out portion tirade in said 'upper face 'adjacent said forward face of said hody said cutout portion providing, together with said forward face of said body, a channel shaped recess made in said tang, said recess having an upright forward face substantially parallel with the forward face of said body and a bottom face extending substantially ,perpendicular to'said forward face of said body, a shelf=like projection at the junction offsaid upright and bottom "faces of'saidchannel shaped recess, a transversely extending groove made in said upright face adjacent the top of :saidjs helf-like projection'and providing i a pivotal surface {having its longitudinal axis extending transversely "of said tang, a rectangular flat keeper element having one rounded longitudinal edge in pivotal eng'agement with said pivotal groove surface and disposed ,within said channel shaped'recess of said tang, a coil spring disposed between the bottom face of the said channel shaped recess and the underface o'f'said keeper to urge the latter upwardly towards the upper face of said tang, and a tooth point mounted for removable engagement on said tang and having a top wall provided in its inner face with a transversely extending groove providiirg 'a curved surface engageable by the outer edge of said keeper,-said curved surface gradually approaching the pivotal axis of said keeper in'a direction away from said body, said spring-urgingsaid keeper in engagement with'sa'id curved surface to lock said tooth point on said tang, and -a bore made in said-tooth point to provide access to the top face of 'said keeper to urge the same against said coil spring into tooth point unlocking position.

7. A digger tooth construction including a body having a tang, -a tooth point removably mounted on-saidtang, and means releasably locking said tooth point on said tang, said locking means comprising a keeper pivotally mounted on said tang, resilient means urging said keeper, anda curved face, disposed on said tooth point and engaged by said keeper, the axis of curvature of said face being offset with respect to the pivotal axis of the keeper, and being disposed on the side thereof opposite the side towards which said resilient means urges said keeper.

Ref'rences'Cited in the file of this patent UNITED STATES PATENTS 

